Aircraft and method for pre-cooling an environmental control system

ABSTRACT

An aircraft includes an environmental control system having a bleed air inlet, a gas turbine engine having at least one low pressure bleed air supply and at least one high pressure bleed air supply, and a turbo air cycle machine having a first turbine section, a second turbine section, a first compressor section, and second compressor section.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a divisional of U.S. patent application Ser. No. 15/244,497, filed Aug. 23, 2016, now allowed, which is incorporated herein by reference in its entirety.

BACKGROUND

Contemporary aircraft have bleed air systems that take hot air from the engines of the aircraft for use in other systems on the aircraft including environmental control systems (ECS) such as air-conditioning, pressurization, and de-icing. The ECS can include limits on the pressure or temperature of the bleed air received from the bleed air systems. Currently, aircraft engine bleed systems make use of a pre-cooler heat exchanger to pre-condition the hot air from the engines to sustainable temperatures, as required or utilized by the other aircraft systems. The pre-cooler heat exchangers produce waste heat, which is typically exhausted from the aircraft without utilization.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of an aircraft having a bleed air system in accordance with various aspects described herein.

FIG. 2 is a schematic cross-sectional view of a portion of an exemplary aircraft gas turbine engine that can be utilized in the aircraft of FIG. 1.

FIG. 3 is a schematic view of a gas turbine engine bleed air system that can be utilized in the aircraft of FIG. 1 in accordance with various aspects described herein.

FIG. 4 is a schematic view of a two gas turbine engine bleed air system architectures that can be utilized in the aircraft of FIG. 1 in accordance with various aspects described herein.

FIG. 5 is a schematic view of a valve that can be utilized in a turbo-ejector as shown in FIGS. 3 and 4.

FIG. 6 is an example a flow chart diagram illustrating a method of providing bleed air to the environmental control system in accordance with various aspects described herein.

DETAILED DESCRIPTION

FIG. 1 illustrates an embodiment of the disclosure, showing an aircraft 10 that can include a bleed air system 20, only a portion of which has been illustrated for clarity purposes. As illustrated, the aircraft 10 can include multiple engines, such as gas turbine engines 12, a fuselage 14, a cockpit 16 positioned in the fuselage 14, and wing assemblies 18 extending outward from the fuselage 14. The aircraft can also include an environmental control system (ECS) 48. The ECS 48 is schematically illustrated in a portion of the fuselage 14 of the aircraft 10 for illustrative purposes only. The ECS 48 is fluidly coupled with the bleed air system 20 to receive a supply of bleed air from the gas turbine engines 12.

The bleed air system 20 can be connected to the gas turbine engines 12 such that high temperature, high pressure air, low pressure air, low temperature, or a combination thereof received from the gas turbine engines 12 can be used within the aircraft 10 for environmental control of the aircraft 10. More specifically, an engine can include a set of bleed ports 24 arranged along the gas turbine engine 12 length or operational stages such that bleed air can be received, captured, or removed from the gas turbine engine 12 as the corresponding set of bleed ports 24. In this sense, various bleed air characteristics, including but not limited to, bleed air mass flow rate (for example, in pounds per minute), bleed air temperature or bleed air pressure, can be selected based on the desired operation or bleed air demand of the bleed air system 20. Further, it is contemplated that ambient air can be used within the aircraft 10 for environmental control of the aircraft 10. As used herein, the environmental control of the aircraft 10, that is, the ECS 48 of the aircraft 10, can include subsystems for anti-icing or de-icing a portion of the aircraft, for pressurizing the cabin or fuselage, heating or cooling the cabin or fuselage, and the like. The operation of the ECS 48 can be a function of at least one of the number of aircraft 10 passengers, aircraft 10 flight phase, or operational subsystems of the ECS 48. Examples of the aircraft 10 flight phase can include, but is not limited to ground idle, taxi, takeoff, climb, cruise, descent, hold, and landing. The demand of the bleed air system 20 by the ECS can be dynamic as, for example, subsystems are needed based on aircraft 10 conditions.

While a commercial aircraft 10 has been illustrated, it is contemplated that embodiments of the invention can be used in any type of aircraft 10. Further, while two gas turbine engines 12 have been illustrated on the wing assemblies 18, it will be understood that any number of gas turbine engines 12 including a single gas turbine engine 12 on the wing assemblies 18, or even a single gas turbine engine mounted in the fuselage 14 can be included.

FIG. 2 illustrates a cross section of the gas turbine engine 12 of the aircraft 10. The gas turbine engine 12 can include, in a serial relationship, a fan 22, a compressor section 26, a combustion section 25, a turbine section 27, and an exhaust section 29. The compressor section 26 can include, in a serial relationship, a multi-stage low pressure compressor 30, and a multi-stage high pressure compressor 32.

The gas turbine engine 12 is also shown including a low pressure bleed port 34 arranged to pull, draw, or receive low pressure bleed air from the low pressure compressor 30 and a high pressure bleed port 36 arranged to pull, draw, or receive high pressure bleed air from the high pressure compressor 32. The bleed ports 34, 36 are also illustrated coupled with various sensors 28, which can provide corresponding output signals. By way of non-limiting example, the sensors 28 can include respective temperature sensors, respective flow rate sensors, or respective pressure sensors. While only a single low pressure bleed port 34 is illustrated, the low pressure compressor 30 can include a set of low pressure bleed ports 34 arranged at multiple stages of the compressor 30 to pull, draw, or receive various bleed air characteristics, including but not limited to, bleed air mass flow rate, bleed air temperature, or bleed air pressure. Similarly, while only a single high pressure bleed port 36 is illustrated, the high pressure compressor 32 can include a set of high pressure bleed ports 36 to pull, draw, or receive various bleed air characteristics, including but not limited to, bleed air mass flow rate, bleed air temperature, or bleed air pressure. Non-limiting embodiments of the disclosure can further include configurations wherein at least one of the low or high pressure bleed port 34, 36 can include a bleed port from an auxiliary power units (APU) or ground cart units (GCU) such that the APU or GCU can provide an augmented pressure and conditioned temperature airflow in addition to or in place of the engine bleed ports 34, 36.

During gas turbine engine 12 operation, the rotation of the fan 22 draws in air, such that at least a portion of the air is supplied to the compressor section 26. The air is pressurized to a low pressure by the low pressure compressor 30, and then is further pressurized to a high pressure by the high pressure compressor 32. At this point in the engine operation, the low pressure bleed port 34 and the high pressure bleed port 36 draw, respectively low pressure air from the low pressure compressor 30 and high pressure air from the high pressure compressor 32 and supply the air to a bleed air system for supplying air to the ECS 48. High pressure air not drawn by the high pressure bleed port 36 is delivered to the combustion section 25, wherein the high pressure air is mixed with fuel and combusted. The combusted gases are delivered downstream to the turbine section 27, which are rotated by the gases passing through the turbine section 27. The rotation of the turbine section 27, in turn, rotates the fan 22 and the compressor section 26 upstream of the turbine section 27. Finally, the combusted gases are exhausted from the gas turbine engine 12 through the exhaust section 29.

FIG. 3 illustrates a schematic view of portions of the aircraft 10 including the gas turbine engine 12, the bleed air system 20, and the ECS 48. As shown, the bleed air system 20 can include a turbo air cycle machine 38 fluidly coupled upstream with the set of gas turbine engine (shown only as a single gas turbine engine 12) and fluidly coupled downstream with the ECS 48. The turbo air cycle machine 38 can include a first turbine section 40 a, a second turbine section 40 b, a first compressor section 42 a, and second compressor section 42 b, all of which can be rotatably coupled on a common shaft 41. In this sense, the turbo air cycle machine 38 can include four wheels: the first and second turbine sections 40 a, 40 b and the first and second compressor sections 42 a, 42 b. The bleed air system 20 of the turbo air cycle machine 38 can include a flow mixer or turbo-ejector 44 located downstream from the turbo air cycle machine 38.

The low pressure and high pressure bleed ports 34, 36 can be fluidly coupled with the turbo air cycle machine 38 by way of a proportional mixing or controllable valve assembly 45. Non-limiting examples of the controllable valve assembly 45 can include mixing, proportional mixing, or non-mixing configurations. In another non-limiting example, the proportional mixing assembly can include a proportional mixing-ejector valve assembly. In one aspect, the proportional mixing-ejector valve assembly or controllable valve assembly 45 can be arranged to supply the low pressure and high pressure bleed air to the turbo air cycle machine 38. Non-limiting examples of the proportional mixing-ejector valve assembly or controllable valve assembly 45 can include a turbo-ejector or mixing-ejector assembly, wherein the high pressure bleed port 36 entrains at least a portion of the low pressure bleed air of the low pressure bleed port 34, or “pulls” air from the low pressure bleed port 34, and provides the mixed, combined, or entrained air to the turbo air cycle machine 38.

Embodiments of the disclosure can include aspects wherein the supply ratio of the low pressure bleed air and high pressure bleed air can be selected to never go below, or alternatively, to never exceed, a predetermined ratio. For example, the aspects of the supply ratio can include, or can be determined to maintain an energy or power balance between the turbine sections 40 a, 40 b and compressor sections 42 a, 42 b of the turbo air cycle machine 38. Another non-limiting example of the proportional mixing-ejector valve assembly or controllable valve assembly 45 can be included wherein the low pressure bleed port 34 of the gas turbine engine 12 can be fluidly coupled with the first compressor section 42 a and second compressor section 42 b of the turbo air cycle machine 38 by way of a first controllable valve 46 and a valve 86. Additionally, the high pressure bleed port 36 of the gas turbine engine 12 can be directly fluidly coupled with the first turbine section 40 a of the turbo air cycle machine 38 by way of a second controllable valve 50. Non-limiting examples of the first or second controllable valves 46, 50 or valve 86 can include a fully proportional or continuous valve.

The controllable valve 46 is illustrated as being combined with a source selection option that includes an integrated check valve 46 a. In this manner the first controllable valve 46 acts as a source selection valve for supplying an ambient airflow or the low pressure bleed airflow 66. In this sense, the first controllable valve 46 can operate to supply only one or the other of the ambient airflow or the low pressure bleed airflow 66. Embodiments of the disclosure can be included wherein the integrated check valve 46 a is selected or configured to provide fluid traversal or selective fluid traversal from the ambient air inlet toward the low pressure bleed airflow 66. In another example, the integrated check valve 46 a can be selected or configured such that the integrated check valve 46 a closes, or self-actuates to a closed position under back pressure, that is when the pressure within the low pressure bleed airflow conduit is higher or greater than the air pressure of the ambient air inlet. In another example, the integrated check valve 46 a can be configured to selected to self-actuate relative to a predetermined air pressure sufficient to operate the turbo air cycle machine 38 In this sense, the integrated check valve 46 a can prevent low bleed pressure air to backflow into the ambient air inlet. Additionally, the integrated check valve can be configured to provide all proportional supplying capabilities described herein.

The addition of the valve 86 allows for selective supplying of airflow to the second compressor section 42 b. Control of the valve 86 allows for pressure matching from the first compressor section 42 a and the second compressor section 42 b. The addition of the second compressor section 42 b in parallel with the first compressor section 42 a increases flow capacity without necessarily increasing outlet pressures or temperatures. Dual compressor sections 42 a, 42 b operating in parallel can operably run “cooler” (i.e. at a lower operating temperature) in their combined capacity than a comparably-operating single compressor section. The second compressor section 42 b in parallel with the first compressor section 42 a may decrease installation footprint in the aircraft depending on their arrangements. This is important as such portions of the turbo air cycle machine 38 may have limited available space on a pylon of the aircraft 10. In another non-limiting example, utilizing both the first and second compressor sections 42 a, 42 b in parallel allows compressor stages unloading based at least partially on a bleed air demand, such as a mass flow (e.g. airflow) demand. In contrast to the aspects described herein, a conventional system may have to unload a higher capacity single compressor.

While a valve 86 is shown and described, additional control mechanisms can be included in aspects of the disclosure in place of the valve 86. In one non-limiting example, the valve 86 can be eliminated in favor of a compressor outlet diffuser that can be included and configured to modulate the exit pressures of the respective compressor sections 42 a, 42 b. In another non-limiting example, the valve 86 can be eliminated in favor of a set of compressor inlet guide vanes that can be configured to vary the flow intake (and thus, capacity) of one compressor section (e.g. the first compressor section 42 a) compared with the other compressor section (e.g. the second compressor section 42 b), until the output pressures match, as described herein. The compressor outlet diffuser or the inlet guide vanes can be operably controlled by way of the controller module 60.

The proportional valve assembly 45 can operate in response to, related to, or as a function of the aircraft flight phase or the rotational speed of the gas turbine engine 12. For example, the rotational speed of the gas turbine engine 12 can vary within an operating cycle, during which the proportional mixing-ejector valve assembly or controllable valve assembly 45 can be adjusted based on gas turbine engine transient or dynamic conditions.

Embodiments of the disclosure can supply any ratio of low pressure bleed air to high pressure bleed air, such as 100% of first bleed air, and 0% of second bleed air. Similarly, the ratio can be predetermined based on dynamic response to engine conditions and to maintain energy balance, an energy balance bleed air demand, or a power balance between the turbine and compressor sections of the turbo air cycle machine assembly.

The low pressure bleed air provided by the low pressure bleed port 34 can be further provided to the first turbine section 40 a downstream of the respective first controllable valve 46 and second controllable valve 50, wherein a fluid coupling providing the low pressure bleed air to the first turbine section 40 a can include a check valve 52 biased in the direction from the low pressure bleed port 34 toward the high pressure bleed port 36 or the first turbine section 40 a of the turbo air cycle machine 38. In this sense, the check valve 52 is configured such that fluid can only flow from the low pressure bleed port 34 to the high pressure bleed port 36 or the first turbine section 40 a of the turbo air cycle machine 38.

Embodiments of the disclosure can be included wherein the check valve 52 is selected or configured to provide fluid traversal from the low pressure bleed port 34 toward the high pressure bleed port 36 under defined or respective pressures of the flow in the respective the low pressure bleed port 34 toward the high pressure bleed port 36. For example, the check valve 52 can be selected or configured to only provide fluid traversal, as shown, the air pressure of the high pressure bleed port 36 is lower or less than the air pressure of the low pressure bleed port 34. In another example, the check valve 52 can be selected or configured such that the valve 52 closes, or self-actuates to a closed position under back pressure, that is when the pressure of the high pressure bleed port 36 is higher or greater than the air pressure of the low pressure bleed port 36. Alternatively, embodiments of the disclosure can include a check valve 52 or the turbo-ejector or the mixing-ejector proportional assembly that is controllable to provide selective fluid traversal from the low pressure bleed port 34 toward the high pressure bleed port 36.

The first compressor section 42 a and second compressor section 42 b of the turbo air cycle machine 38 can include a compressor output 54. The addition of a check valve 88 prevents backflow or pressure from the first compressor section 42 a to the second compressor section 42 b.

A decoupler 80 can be operably coupled to the portion of the common shaft 41 between the first compressor section 42 a and the second compressor section 42 b. The decoupler 80 can be any suitable mechanism configured to uncouple the second compressor section 42 b from the common shaft 41 or a remainder of the common shaft 41. The decoupler 80 can include, but is not limited to, a clutch or mechanical fuse disconnect. It will be understood that the decoupler 80 can be optional and that the second compressor section 42 b can alternatively always be coupled to the common shaft 41. The decoupler 80 is configured to decouple the second compressor section 42 b from the first compressor section 42 a and allows for reduced capacity as a function of occupancy of the aircraft 10. It is contemplated that the decoupler 80 can be controlled automatically by a processor, such as the controller module 60, or manually before engine start as selected by the crew or by a user, based on the mission requirements or bleed air demand. In one non-limiting example, the decoupler 80 can operably de-couple the second compressor section 42 b from the first compressor section 42 a or common shaft 41 while the compressor sections 42 a, 42 b are operating, such as in-flight. In another non-limiting example, the decoupler 80 can only operably re-couple the second compressor section 42 b to the first compressor section 42 a or common shaft 41 when the compressor sections 42 a, 42 b are not operating. The re-coupling only while the compressor sections 42 a, 42 b are not operating can be due to, for instance, possible damage caused to bearings, gears, the common shaft 41, or the like, if re-coupled was enabled during operations.

The first turbine section 40 a can include a first turbine output 56 defining a cooled airflow 70. The first turbine output 56 can be optionally and proportionally supplied to the second turbine section 40 b. More specifically, the first turbine output 56 is illustrated at being fluidly coupled to the second turbine section 40 b. The first turbine output 56 can also be fluidly coupled to a bypass conduit 43. As illustrated the bypass conduit 43 can fluidly couple the fluid output 56 of the first turbine section 40 a to the downstream turbo-ejector 44 such that the fluid output 56 need not be provided to the second turbine section 40 b. A bypass valve 47 is included to selectively control fluid flow through the bypass conduit 43 to the downstream turbo-ejector 44. The bypass valve 47 can be any suitable valve including, but not limited to, a proportional valve or a continuous valve. The second turbine section 40 b can include a second turbine output 71 defining an airflow. First turbine output 56 that bypasses the second turbine section 40 b has been schematically illustrated with arrows and defines a bypass airflow 73.

The compressor output 54, any second turbine output 71 and any bypass airflow 73 are fluidly combined downstream of the turbo air cycle machine 38. The flow mixer is arranged to fluidly combine the compressor output 54, any second turbine output 71, and any bypass airflow 73 to a common mixed flow 74 that is supplied to the bleed air inlet 49 of the ECS 48. In this manner, the downstream turbo-ejector 44 fluidly combines fluid outputs from the first turbine section 40 a, in the form of bypass airflow 73, and the second turbine section 40 b, in the form of a second turbine output 71, with fluid output from the compressor section, in the form of compressor output 54, into a common flow 74 that is supplied to the bleed air inlet 49 of the ECS 48. In this sense, the bleed air system 20 preconditions the bleed air before the bleed air is received by the bleed air inlet 49 of the ECS 48.

The second turbine output 71 and bypass airflow 73 are fluidly coupled to define a combined turbine output airflow 75 or cooled airflow. In the illustrated embodiment of the flow mixer, the turbo-ejector 44 pressurizes the turbine output airflow 75 as it traverses a narrow portion 58, or “throat” of the turbo-ejector 44, and fluidly injects the compressor output 54 into the narrow portion 58 of the turbo-ejector 44. The injection of the compressor output 54 into the pressurized turbine output airflow 75 fluidly combines the compressor output 54 with the turbine output airflow 75. The common airflow stream 74 of the turbo-ejector 44 is fluidly coupled downstream with the ECS 48 at a bleed air inlet 49. Embodiments of the disclosure can be included wherein the compressor output 54, the turbine output airflow 75, or the turbo-ejector 44 (e.g. downstream from the narrow portion 58) can include a set of sensors 28.

The turbo-ejector 44, sometimes referred to as an “ejector pump” or an “ejector valve,” works by injecting air from a higher pressure source into a nozzle at the input end of a venturi restriction, into which a lower pressure air source is also fed. Air from the higher pressure source is emitted downstream into the lower pressure flow at high velocity. Friction caused by the adjacency of the airstreams causes the lower pressure air to be accelerated (“entrained”) and drawn through the venturi restriction. As the higher pressure air ejected into the lower pressure airstream expands toward the lower pressure of the low pressure air source, the velocity increases, further accelerating the flow of the combined or mixed airflow. As the lower pressure air flow is accelerated by its entrainment by the higher pressure source, the temperature and pressure of the low pressure source are reduced, resulting in more energy to be extracted or “recovered” from the turbine output. Non-limiting embodiments of the disclosure can be included wherein the high pressure air source is at a higher or greater temperature than the low pressure air source. However, in alternative embodiments of the disclosure, the entrainment and mixing process can occur without the high pressure air source having a higher or greater temperature than the low pressure air source. The above-described embodiments are application to the turbo-ejector 44 illustrated downstream of the turbo air cycle machine 38, as well as to the turbo-ejector embodiment of the controllable valve assembly 45.

The aircraft 10 or bleed air system 20 can also include a controller module 60 having a processor 62 and memory 64. The controller module 60 or processor 62 can be operably or communicatively coupled to the bleed air system 20, including its sensors 28, the first controllable valve 46, the second controllable valve 50, the bypass valve 47, and the ECS 48. The controller module 60 or processor 62 can further be operably or communicatively coupled with the sensors 28 dispersed along the fluid couplings of the bleed air system 20. The memory 64 can include random access memory (RAM), read-only memory (ROM), flash memory, or one or more different types of portable electronic memory, such as discs, DVDs, CD-ROMs, etc., or any suitable combination of these types of memory. The controller module 60 or processor 62 can further be configured to run any suitable programs. Non-limiting embodiments of the disclosure can be included wherein, for example, the controller module 60 or processor 62 can also be connected with other controllers, processors, or systems of the aircraft 10, or can be included as part of or a subcomponent of another controller, processor, or system of the aircraft 10. In one example, the controller module 60 can include a full authority digital engine or electronics controller (FADEC), an onboard avionic computer or controller, or a module remoted located by way of a common data link or protocol.

A computer searchable database of information can be stored in the memory 64 and accessible by the controller module 60 or processor 62. The controller module 60 or processor 62 can run a set of executable instructions to display the database or access the database. Alternatively, the controller module 60 or processor 62 can be operably coupled to a database of information. For example, such a database can be stored on an alternative computer or controller. It will be understood that the database can be any suitable database, including a single database having multiple sets of data, multiple discrete databases linked together, or even a simple table of data. It is contemplated that the database can incorporate a number of databases or that the database can actually be a number of separate databases. The database can store data that can include, among other things, historical data related to the reference value for the sensor outputs, as well as historical bleed air system 20 data for the aircraft 10 and related to a fleet of aircraft. The database can also include reference values including historic values or aggregated values.

During gas turbine engine 12 operation, the bleed air system 20 supplies a low pressure bleed airflow 66 along the low pressure bleed port 34 and a high pressure bleed airflow 68 along the high pressure bleed port 36, as previously explained. The high pressure bleed airflow 68 is delivered to the first turbine section 40 a and optionally the second turbine section 40 b of the turbo air cycle machine 38, which in turn interacts with the turbine(s) to drive the rotation of the first turbine section 40 a and the second turbine section 40 b. The high pressure bleed airflow 68 exits the first turbine section 40 a at the first turbine output 56 as a first turbine output airflow. A first portion 66 a of the low pressure bleed airflow 66 can be delivered to the first compressor section 42 a, a second portion 66 b of the low pressure bleed airflow 66 can be delivered to the second compressor section 42 b of the turbo air cycle machine 38, and a third portion of the low pressure bleed airflow 66 can be delivered to the first turbine section 40 a and optionally the second turbine section 40 b of the turbo air cycle machine 38, depending on the operation of the check valve 52 or upstream turbo-ejector or mixing-ejector proportional assembly, or the respective airflows 66, 68 of the respective low pressure bleed port 34 and high pressure bleed port 36, as explained herein. For example, embodiments of the disclosure can include operations wherein the airflow delivered to the first turbine section 40 a and optionally the second turbine section 40 b can include entirely low pressure bleed airflow 66, no low pressure bleed airflow 66, or a portion therebetween. The second portion of the low pressure bleed airflow 66 can also be utilize to drive the rotation of the first turbine section 40 a and the second turbine section 40 b, such as when the controllable valve 50 is set to provide no high pressure bleed airflow 68.

It will be understood that the controller module 60 is configured to operate the bypass valve 47 to supply an amount of the first turbine output 56 to the second turbine section 40 b of the turbo air cycle machine 38. It is contemplated that the controller 60 can operate the bypass valve 47 based on input from any of the sensors 28 including temperature sensors of the combined airflow stream 74, the turbine output airflow 75, the first turbine output 56, any combination thereof, etc. Embodiments of the disclosure can include operations wherein the first turbine output 56 can supply less than 100% of the cooled air stream to the second turbine section 40 b, or wherein the first turbine output 56 can supply 100% of the cooled air stream to the second turbine section 40 b.

The first portion 66 a of the low pressure bleed airflow 66 can be compressed by the rotation of the first compressor section 42 a. The second portion 66 b of the low pressure bleed airflow 66 can be compressed by the second compressor section 42 b, which is rotatably coupled with the first turbine section 40 a and the second turbine section 40 b. The compressed low pressure bleed air exits the first compressor section 42 a and second compressor section 42 b at the compressor output 54 as compressor output airflows 72 a and 72 b, which can be combined to form compressed airflow 72 c. The turbine output airflow 75 and the compressor output airflow 72 c are combined in the turbo-ejector 44 to form the combined airflow stream 74, which is further provided to the ECS 48. In this sense, the combined airflow stream 74 can be expressed as a composition or a ratio of the low pressure and high pressure bleed airflow 66, 68, or a composition of a ratio of the combined turbine output and compressor output airflows 75, 72 c.

The compression of the low pressure airflow 66, by the first compressor section 42 a and second compressor section 42 b, generates a higher pressure and higher temperature compressor output airflow 72 c, compared with the low pressure airflow 66. Additionally, the airflows received by the first turbine section 40 a and the second turbine section 40 b, that is, the high pressure airflow 68 and selective low pressure airflow 66 via the check valve 52 via a turbo-ejector or mixing-ejector proportional assembly, generates a lower pressure and a lower temperature turbine output airflow 75, compared with the first turbine section 40 a and the second turbine section 40 b input airflows 66, 68. In this sense, the first compressor section 42 a and second compressor section 42 b outputs or emits a hotter and higher pressure airflow 72 c, while the first turbine section 40 a outputs or emits a cooler and lower pressure airflow 70, compared with the relative input airflows 66, 68. The second turbine section 40 b outputs or emits an even cooler airflow 71 as compared with the airflow 70.

The controller module 60 or processor 62 can be configured to operably receive a bleed air demand, generated by, for example, the ECS 48. The bleed air demand can be provided to the controller module 60 or processor 62 by way of a bleed air demand signal 76, which can include bleed air demand characteristics included, but not limited to, flow rate, temperature, pressure, or mass flow (e.g. airflow). In response to the bleed air demand signal 76, the controller module 60 or processor 62 can operably supply proportional amounts of the low pressure bleed airflow 66 and high pressure bleed airflow 68 to the turbo air cycle machine 38. The proportionality of the low pressure bleed airflow 66, and the high pressure bleed airflows 68 can be controlled by way of the respective first or second controllable valves 46, 50, and by selective operation of the check valve 52 or mixing-ejector proportional assembly.

The proportional supplying of the low pressure and high pressure bleed airflows 66, 68 can be directly or geometrically proportional to the turbine output airflow 75 and compressor output airflow 72 c, or the turbine air cycle machine 38 operations. The turbine output airflow 75 and compressor output airflow 72 c are combined downstream of the turbo air cycle machine 38, and the combined airflow stream 74 is provided to the ECS 48. In one non-limiting example, the compressor output airflow 72 c can drive the turbine output airflow 75 into the narrow portion 58 and mix under sonic conditions. The mixed flow pressure will recover statically through the combined airflow stream 74 to output the turbo-ejector 44 at desired conditions. In this sense, the combined airflow stream 74 is conditioned by way of operation of the bleed air system 20, controllable valves 46, 50, check valve 52, turbo-ejector or mixing-ejector proportional assembly, turbo air cycle machine 38, the combining of the turbine output airflow 75 and the compressor output airflow 72 c, or any combination thereof, to meet or satisfies the ECS 48 demand for bleed air.

One of the controller module 60 or processor 62 can include all or a portion of a computer program having an executable instruction set for determining the bleed air demand of the ECS 48, proportionally or selectively supplying the low pressure or high pressure bleed airflows 66, 68, operating the controllable valves 46, 50, the check valve's 52 or turbo-ejector or mixing-ejector proportional assembly's operation in response to the respective high pressure and low pressure airflows 66, 68, or a combination thereof. As used herein, “proportionally or selectively supplying” the low pressure or high pressure bleed airflows 66, 68 can include altering or modifying at least one of the low pressure or high pressure bleed airflows 66, 68. For example, proportionally or selectively supplying the low pressure or high pressure bleed airflows 66, 68 can include altering the low pressure bleed airflow 66 without altering the high pressure bleed airflow 68, or vice versa. In another example proportionally or selectively supplying the low pressure or high pressure bleed airflows 66, 68 can include altering the low pressure bleed airflow 66 and the high pressure bleed airflow 68. Also as used herein, “proportionally” supplying the low pressure or high pressure bleed airflows 66, 68 can include altering or modifying the ratio of low pressure bleed airflow 66 to high pressure bleed airflow 68, based on the total bleed airflow 66, 68 supplied. Stated another way, the proportions of low or high pressure bleed airflow 66, 68 can be altered or modified, and a proportional ratio can be included or described based on the total airflow of the low and high pressure bleed airflows 66, 68.

Regardless of whether the controller module 60 or processor 62 controls the operation of the bleed air system 20, the program can include a computer program product that can include machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available media, which can be accessed by a general purpose or special purpose computer or other machine with a processor. Generally, such a computer program can include routines, programs, objects, components, data structures, and the like, that have the technical effect of performing particular tasks or implementing particular abstract data types. Machine-executable instructions, associated data structures, and programs represent examples of program code for executing the exchange of information as disclosed herein. Machine-executable instructions can include, for example, instructions and data, which cause a general-purpose computer, special purpose computer, or special purpose processing machine to perform a certain function or group of functions.

While the bleed air characteristics of the low pressure or high pressure bleed airflows 66, 68 can remain relatively consistent or stable during a cruise portion of a flight by the aircraft 10, varying aircraft 10 or flight characteristics, such as altitude, speed or idle setting, heading, solar cycle, or geographic aircraft location can produce inconsistent airflows 66, 68 in the bleed air system 20. Thus, the controller module 60 or processor 62 can also be configured to operate the bleed air system 20, as explained herein, in response to receiving a set of sensor input values received by the sensors 28 dispersed along the fluid couplings of the bleed air system 20. For example, the controller module 60 or processor 62 can include predetermined, known, expected, estimated, or calculated values for the set of airflows 66, 66 a, 66 b, 68, 70, 71, 72 a, 72 b, 72 c, 73, 74, 75 traversing the bleed air system 20. In response to varying aircraft 10 or flight characteristics, the controller module 60 or processor 62 can alter the proportional supplying of the low pressure or high pressure bleed airflows 66, 68 in order to meet or satisfy the bleed air demand for the ECS 48. Alternatively, the memory 64 can include a database or lookup table such that a proportional supplying values related to the low pressure or high pressure bleed airflows 66, 68 can be determined in response to the controller module 60 receiving a set or subset of sensor 28 readings, measurements, or the like.

While sensors 28 are described as “sensing,” “measuring,” or “reading” respective temperatures, flow rates, or pressures, the controller module 60 or processor 62 can be configured to sense, measure, estimate, calculate, determine, or monitor the sensor 28 outputs, such that the controller module 60 or processor 62 interprets a value representative or indicative of the respective temperature, flow rate, pressure, or combination thereof. Additionally, sensors 28 can be included proximate to, or integral with additional components not previously demonstrated. For example, embodiments of the disclosure can include sensors 28 located to sense the combined airflow stream 74, or can include sensors 28 located within the narrow portion 58, or “throat” of the turbo-ejector 44.

In another non-limiting example of responsive operation, the controller module 60 can operate the second controllable valve 50 based on a bleed air demand of the bleed air system 20. The bleed air demand can include, for example, a desired or demanded output airflow stream 74 from the turbo-ejector 44. In this sense, the controller module 60 can operate the second controllable valve 50 based on a desired or demanded output airflow stream 74 of the turbo-ejector 44. The controller module 60 can further operate, for example, the bypass valve 47 such that the bypass airflow 73 of the first turbine output 56, when combined with the second turbine output 71, affects a cooling of the turbine output airflow 75, which in turn operably affects or controls the temperature of the output airflow stream 74, based on a bleed air demand of the bleed air system 20, such as a desired or demanded temperature of the output airflow stream 74. Thus, during operation, if the temperature of the output airflow stream 74 is below or less than a threshold, demanded, or desired temperature, as sensed by a sensor 28, the bypass valve 47 can be operably opened such that air will flow from the first turbine output 56 to the turbine output airflow 75. In this sense, the opening of the bypass valve 47 can operably raise the temperature of the output airflow stream 74. During operation, if the temperature of the output airflow stream 74 is above or greater than the threshold, demanded or desired temperature of the output airflow stream 74, as sensed by a sensor 28, the bypass valve 47 can be operably closed such that no bypass airflow 73 is provided to the turbine output airflow 75, and ultimately, the output airflow stream 74. In this sense, the closing of the bypass valve 47 can operably lower the temperature of the output airflow stream 74.

In another non-limiting example of responsive operation, the controller module 60 can operate the second controllable valve 50 based on a bleed air demand including a desired or demanded pressure of the output airflow stream 74. If the pressure of the output airflow stream 74, as sensed by a sensor 28, is below or less than a threshold, demanded, or desired pressure, the second controllable valve 50 can operably open to provide or allow a portion or additional high pressure bleed airflow 68 to the turbo air cycle machine 38. As the second controllable valve 50 provides or allows high pressure bleed airflow 68 to the turbo air cycle machine 38, the turbine sections 40 a 40 b will rotate faster, generating more rotational power, which in turn, affects the total amount of power for the compressor sections 42 a, 42 b to absorb. In this sense, the second controllable valve 50 can be operated to modify or adjust the pressure of the output airflow stream 74 based on a desired or demanded pressure.

In another non-limiting responsive operation, the first controllable valve 46 can be controllably operated by the controller module 60, and based on the compressor output airflow 72 c, as sensed by the sensor 28, maintain a power balance between the turbine sections 40 a, 40 b generating power and the compressor sections 42 a, 42 b absorbing power. In this sense, the controller module 60 can be configured to operate the first and second controllable valves 46, 50 simultaneously.

The aforementioned configuration and operation of the valves 46, 50, 47 allows for, causes, or affects the adiabatic change in efficiency of the turbo-ejector.

Embodiments of the disclosure can be included wherein the controller module 60 or processor 62 can be configured to operate the bleed air system 20 to account for sensor 28 measurements in the set or a subset of the airflows 66, 68, 70, 71, 72 a, 72 b, 72 c, 73, 74, 75.

In another embodiment of the disclosure, the bleed air system 20 can operate without feedback inputs, that is, without the controller module 60 or processor 62 receiving sensed information from the sensors 28. In this alternative configuration, the controller module 60 or processor 62 can be configured to operate the first or second controllable valves 46, 50, and the like based on a continuous operation of the aircraft 10, given the dynamic responses as observed during the aircraft 10 flight phases.

The above described disclosure with the second stage turbine 40 b allows the turbo air cycle machine 38 to have increased cooling capacity, allows for higher bleed stage extraction from the gas turbine engine 12, and allows for increased turbine power generation as compared to a turbo air cycle machine with only one turbine section. The inclusion of the second stage turbine bypass allows second stage unloading at lower high pressure bleed port extraction stages, reduces unnecessary second turbine stage excess power, and allows second stage turbine exit temperature control.

FIG. 4 is a schematic view of a two turbine engine bleed air system architecture that can be utilized in the aircraft 10. The bleed air system illustrated in FIG. 3 has been illustrated as being incorporated into both sides of the aircraft 10. Like parts have been identified with like numerals and the above description of such parts applies. It will be understood that such architecture is by way of non-limiting example only.

FIG. 4 illustrates that the combined airflow stream 74 from left and right turbo-ejectors 44 can be fluidly coupled to the ECS 48. The ECS 48 is illustrated as including both a left air conditioning pack 100 and a right air conditioning pack 102. The combined airflow stream 74 from the turbo-ejectors 44 can be fluidly coupled to such air conditioning packs 100 and 102 through any suitable conduits and valving illustrated schematically. The quantity of combined airflow stream 74 to the air conditioning packs 100 and 102 is regulated by the flow control valve 112. One flow control valve 112 is installed for each of the air conditioning packs 100 and 102.

An isolation valve 110 is also illustrated as being included. The isolation valve 110 is normally closed and prevents air from the left side bleed air system 20 from reaching the right air conditioning pack 102 and vice versa. The isolation valve 110 can be opened in the event of loss of one of the bleed air systems 20. The output from the turbo-ejectors 44 can also be supplied through the flow control valve 112 to anti-icing systems 116 via valves 114.

The air conditioning packs 100 and 102 can be fluidly coupled to a mixing manifold 104, which can ultimately provide airflow to the cabin 106 and the flight deck 108. More specifically, exhaust flows from the air conditioning packs 100 and 102 are fluidly coupled to the mixing manifold 104 where they are typically mixed with filtered air. Airflow from the mixing manifold 104 is directed to distribution nozzles to supply the cabin 106 and the flight deck 108. Check valves 118 can be included between the air conditioning packs 100 and 102 and the mixing manifold 104.

FIG. 5 illustrates in more detail that a valve 130 can be included in the flow mixer or turbo-ejector 44 located downstream from the turbo air cycle machine 38. By way of non-limiting example, the valve 130 can include a controllable pintle injector utilized to control the injection of the compressor output 54 into the throat portion 58 of the turbo-ejector 44. The valve 130 can include a slidable needle 132 linearly actuated in either directions as indicated by arrow 134. The slidable needle 132 or pintle can be proportionally & linearly actuated to increase or decrease the nozzle exit flow area discharge into the throat 58 which can in turn operably affect the ratio of entrainment of lower pressure air 75 versus injected higher pressure air 72 c and the overall turbo ejector efficiency as a pumping mechanism. The varying of lower pressure mass airflow 75 versus higher pressure mass airflow 72 c ratio increases or decreases the range of operability of the turbo ejector which affects its efficiency. In this sense, efficiency is a function of pressure, temperature, and mass flow ratios. Thus, any variation of pressure, temperature, and mass flow ratios operably affects the efficiency output rating. The needle 132 may be controllably operated, for example, via the controller module 60 to maintain a pre-determined mass flow ratio, to maintain an efficiency rating, or to operate the turbo-ejector 44 relative to a predetermined threshold or threshold range.

Such a valve allows control of turbo ejector efficiency and allows control of the low pressures and high pressure mass flow ratios.

FIG. 6 illustrates a flow chart demonstrating a non-limiting example method 200 of providing bleed air to the ECS 48 of an aircraft using at least one gas turbine engine 12. The method 200 begins at 210 by determining a bleed air demand for the ECS 48. Determining the bleed air demand can include determining at least one of an air pressure, an air temperature, or a flow rate demand for the ECS 48, or a combination thereof. The bleed air demand can be a function of at least one of the number of aircraft passengers, aircraft flight phase, or operational subsystems of the ECS 48. The bleed air demand can be determined by the ECS 48, the controller module 60, or the processor 62 based on the bleed air demand signal 76.

Next at 220, the controller module 60 or the processor 62 operably controls the controllable valve assembly 45 to proportionally supply the low pressure and high pressure bleed air such that turbo air cycle machine 38 emits a cooled air stream from the first turbine section 40 a in the form of bypass airflow 73 or the second turbine section 40 b and a compressed air stream from the compressor sections 42 a, 42 b. As used herein, a “cooled” airstream can describe an airflow having a lower temperature than the airflow received by the first turbine section 40 a. Embodiments of the disclosure can include, but are not limited to, supplying up to 100% of the combined airflow stream 74 of one of the low pressure or high pressure bleed airflow and 0% of the corresponding other of the low pressure or high pressure bleed airflow. Another example embodiment of the disclosure can include, but is not limited to, proportionally supplying the low pressure and high pressure bleed airflows wherein the proportionally supplying is related to, or is a function of the aircraft flight phase or rotational speed of the gas turbine engine 12. The proportionally supplying of the bleed air can include continuously proportionally supplying the bleed air, that is, repeatedly altering the proportional supplying of the low pressure and high pressure bleed airflows over a period of time, or indefinitely during the flight of the aircraft.

At 230, the bypass valve 47 can be controlled by the controller module 60 or the processor 62 such that output from the first turbine section 40 a is directed to the second turbine section 40 b to create a further cooled air stream or second turbine output 71 or through the bypass conduit 43 to create a bypass airflow 73. As used herein “further cooled” air stream describes that the air stream of the second turbine output 71 has a lower temperature than the output of the first turbine section 40 a that is directed to the second turbine section 40 b. Embodiments of the disclosure can include, but are not limited to the bypass valve 47 being controlled to supply any amount from 0% to 100% of the first turbine output 56 to the second turbine section 40 b and the remainder to the bypass conduit 43. The controller module 60 or the processor 62 can control the bypass valve 47 in order to control the exit temperature of the combined airflow stream 74.

At 240, the valve 86 can be controlled by the controller module 60 or the processor 62 such that ambient air 51 or low pressure bleed air 66 can be selectively supplied to the second compressor section 42 b in addition to the first compressor section 42 a. It will be understood that the second compressor section 42 b is supplied in parallel with the first compressor section 42 a. It is contemplated that the controller module 60 or the processor 62 can determine flow rates to be supplied to the first compressor section 42 a and the second compressor section 42 b based on the determined flow rate demand from the ECS 48 and control the valve 86 based thereon such that the supplying is controlled such that the conditioned air stream meets or satisfies the determined bleed air demand.

It will be understood that the turbo air cycle machine 38 emits a cooled air stream from the first turbine section 40 a in the form of bypass airflow 73 or the second turbine section 40 b in the form of a further cooled airflow 71 and a compressed air stream 72 a from the first compressor section 42 a and optionally a compressed air stream 72 b from the second compressor section 42 b.

At 250, the method 200 continues by combining the cooled air stream, in the form of the bypass airflow 73, the further cooled airflow stream in the form of the second turbine output 71 and the compressed air stream(s) 72 a, 72 b, 72 c to form a conditioned or combined airflow stream 74. It will be understood that the compressed air stream 72 a from the first compressor section 42 a can be combined with the compressed air stream 72 b from the second compressor section 42 b to form a combined compressed airflow stream 72 c. The combined compressed air stream 72 c can then be combined with at least one of the bypass airflow 73 or the second turbine output 71 to form the conditioned air stream 74. Alternatively, if no airflow is supplied to the second compressor section 42 b, then the compressed airflow stream 72 a can be combined with at least one of the bypass airflow 73 or the second turbine output 71 to form the conditioned air stream 74.

The proportional supplying the ambient air or low pressure and the high pressure bleed air at 220, the selectively supplying at 230 and selectively supplying the cooled air to the second turbine section 40 b at 240 is controlled by the controller module 60 or processor 62 such that the combined airflow stream 74 meets or satisfies the bleed air demand for the ECS 48 as determined at 210. Aspects of the method can also be included wherein the combined airflow stream 74 can be altered, modified, or the like, by way of operating the controllable pintle injector, the valve 130, or the slidable needle 132.

The sequence depicted is for illustrative purposes only and is not meant to limit the method 200 in any way as it is understood that the portions of the method can proceed in a different logical order, additional or intervening portions can be included, or described portions of the method can be divided into multiple portions, or described portions of the method can be omitted without detracting from the described method.

For example, it is contemplated that the method can include receiving an output signal from a temperature sensor 28 related to a temperature of the conditioned air stream or combined airflow stream 74. As determining the bleed air demand at 310 can include determining an air temperature demand for the ECS 48 the controller 60 or processor 62 can calculate or otherwise determine an amount of cooled air stream to be supplied to the second turbine section 40 b based on the determined air temperature demand and the output signal from the temperature sensor 28. It is contemplated that this can include continuously determining the amount of cooled air stream to be supplied to the second turbine section 40 b.

The method can include proportionally supplying at least one of a first compressor section or a second compressor section based on desired flow capacity. The method can also include proportionally supplying low pressure bleed air and high pressure bleed air from a compressor of the gas turbine engine to a turbo air cycle machine to precondition the bleed air according to operational demands of the ECS wherein the preconditioning comprises selectively providing a fluid output emitted from a first turbine section 40 a of the turbo air cycle machine 38 to a second turbine section 40 b of the turbo air cycle machine 38 for further cooling. As described above this can be based on temperature demands of the ECS.

In one non-limiting example, the controller module 60 can control the controllable valve 50 to be opened or closed as a master control to operably control an exit pressure of the combined airflow stream 74 of the turbo-ejector 44. In a non-limiting example, the controller module 60 can also control the first controllable valve 46 as a slave to the master control, to operably control the energy balance between the turbine sections 40 a, 40 b and the compressor sections 42 a, 42 b. This can be considered a master control in baseline system logic. The controller module 60 can control the controllable valve 46 to control a total compressor power balance in the turbo air cycle machine 38 and such can be a slave control to that of the controllable valve 50. The controller module 60 can control the source selected by the controllable valve 46 and such a source selection can be set based on the mission schedule of the aircraft 10. The controller module 60 can control the controllable valve 86 to match outlet pressures from the first compressor section 42 a and second compressor section 42 b. In a non-limiting example, the check valve 52 can be closed or self-closed by default.

In one non-limiting example, the controller module 60 can also control the bypass valve 47, and therefore an exit temperature of the combined airflow stream 74 of the turbo-ejector 44 simultaneously, but independently with the controllable valve 46. For instance, in some cases, lowering or reducing the exit pressure of the combined airflow stream 74 by way of the second controllable valve 50 operation will also lower or reduce the exit temperature of the combined airflow stream 74. In this sense, the operation of the second controllable valve 50 can be included as an override consideration to reduce or lower at least one of the temperature or pressure of the combined airflow stream 74 if operation of the bypass valve 47 is inadequate, insufficient, or otherwise unable to operably control the temperature or pressure of the combined airflow stream 74, as described herein. For instance, if the bypass valve 47 were to fail or be rendered inoperable, or if the bypass valve 47 is fully opened or closed despite the inability to alter the combined airflow stream 74 as desired, the system logic can be configured to operate the second controllable valve 50 to alter or adjust the pressure received by the turbine sections 40 a, 40 b, to operably alter or adjust the temperature of the combined airflow stream 74.

In another non-limiting example, the controller 60 can control the operation of the valve 130 to operably control the low pressure and high pressure mass flow rates, target efficiency, or the like, as described herein, based on desired efficiency of the turbo-ejector 44.

In another non-limiting example the controller module 60 can operate in an alternate system logic, including but not limited to an emergency operation, for example, such as when the high pressure bleed source is disabled, removed, or shut down. In such an operation the controllable valve 50 is closed and the controller module 60 can control the controllable valve 46 to control an exit pressure of the combined airflow stream 74 of the turbo-ejector 44 as a master control. In this scenario, the check valve 52 can be open, allowing or enabling low pressure bleed airflow 66 to flow to the turbine sections 40 a, 40 b. The controller module 60 can control the bypass valve 47 to operably control an exit temperature of the combined airflow stream 74 of the turbo-ejector 44. With the inclusion of the valve 130, the controller 60 can control the operation of the valve 130 to operably control the energy balance by adjusting the low and high pressure mass flow rations as needed, independent of efficiency considerations. In another example, the controller 60 can control the operation of the valve 130 as described, but by operably controlling the energy balance or the high pressure/low pressure mass flow ratio as needed, or within a predetermined threshold or threshold range, such as to prevent back flow to the turbine outputs.

In another non-limiting example of the method, the selectively supplying airflow to the set of compressors can include operating the valve 86 based on a desired compressor output airflow 72 c. For example, the controller module 60 can control the valve 86 to be opened or closed based on a sensing or measuring of the compressor output airflows 72 a and 72 b. For instance, the controller module 60 can control the valve 86 such that the compressor output pressure 72 a, 72 b are matched, even, or similar in temperature, massfow, or a combination thereof. Aspects of the disclosure can be included wherein, for example, the controller module 60 or operation of the valve 86 can take into account for dissimilar or variations in pressure drop resistance in the inlet path to the first compressor section 42 a compared with the resistance in the inlet path to the second compressor section 42 b, and how that can affect the matching of the resulting compressor output pressures 72 a, 72 b, as described herein. In this sense, the controller module 60 can control the valve 86 as a slave to the first controllable valve 46, to operably control the total compressor output 72 c, dependent upon the controlling of the power balance via the first controllable valve 46.

In yet another non-limiting example, the selectively supplying airflow to the set of compressors can include not supplying air to the second compressor section 42 b. In this instance, the selectively supplying airflow to the set of compressors can include operating the valve 86, for example, by way of the controller module 60, based on the occupancy number of passengers on the flight. In this sense, the occupancy number of passengers on the flight can modify the bleed air demand. The controllable operation of the valve 86 can thus be set, changed, modified, or enable after the crew or a user enters an occupancy number into an onboard computer system, which can translate, compute, or the like, a bleed air demand, thus enabling a single or dual compressor section 42 a, 42 b operation.

Selectively supplying airflow to the set of compressors can further include de-coupling the second compressor section 42 b from the common shaft 41, for instance, prior to flying the aircraft or starting the gas turbine engine. Should the bleed air demand result in a single compressor section 42 a operation, the valve 86 can be set to not provide airflow to the second compressor section 42 b, and the decoupler 80 can be activated or enabled to mechanically de-couple the second compressor section 42 b from the common shaft 41. More specifically, the controller 60 or processor 62 can operate the decoupler 80 so that the second compressor section 42 b is not operably coupled to the common shaft 41 when air is not provided to the second compressor section 42 b, or when no additional flow capacity is needed.

Many other possible embodiments and configurations in addition to that shown in the above figures are contemplated by the present disclosure. For example, embodiments of the disclosure can be included wherein the second controllable valve 50 could be replaced with a bleed ejector or mixing valve also coupled with the low pressure bleed port 34. In another non-limiting example, the turbo-ejector 44, the compressor output 54, or the first turbine output 56 can be configured to prevent backflow from downstream components from entering the turbo air cycle machine 38.

In yet another non-limiting example embodiment of the disclosure, the check valve 52 or turbo-ejector proportional assembly can include, or can be replaced by a third controllable valve, and controlled by the controller module 60 as explained herein, to operate or effect a ratio of low pressure bleed airflow 66 and high pressure bleed airflow 68 supplied to the first turbine section 40 a and optionally the second turbine section 40 b. Additionally, the design and placement of the various components such as valves, pumps, or conduits can be rearranged such that a number of different in-line configurations could be realized.

The embodiments disclosed herein provide a method and aircraft for providing bleed air to an environmental control system. The technical effect is that the above described embodiments enable the preconditioning of bleed air received from a gas turbine engine such that the conditioning and combining of the bleed air is selected to meet or satisfy a bleed air demand for the environmental control system. Further, the turbo ejector allows for mixing of two different air streams at different pressure while recovering the energy otherwise associated with backpressure of the turbine.

One advantage that can be realized in the above embodiments is that the above described embodiments have superior bleed air conditioning for the ECS without wasting excess heat, compared with traditional pre-cooler heat exchanger systems. Another advantage that can be realized is that by eliminating the waste of excess heat, the system can further reduce bleed extraction from the engine related to the wasted heat. By reducing bleed extraction, the engine operates with improved efficiency, yielding fuel cost savings, and increasing operable flight range for the aircraft.

Yet another advantage that can be realized by the above embodiments is that the bleed air system can provide variable bleed air conditioning for the ECS. The variable bleed air can meet or satisfy a variable demand for bleed air in the ECS due to a variable ECS load, for example, as subsystems are operated or cease to operate. This includes the advantage of the ability to transform low stage bleed air to air that is suitable for the ECS. Low pressure bleed air pressure and ambient air pressure can be augmented to a desired pressure for the ECS.

Yet another advantage includes that waste cooling energy can be utilized to further assist cooling temperatures of the air for use in the ECS.

Yet another advantage includes the capability of operating first and second compressor sections in parallel, which allows compressor stages unloading based at least partially on a bleed air demand, such as a mass flow (e.g. airflow) demand, compared with operating or unloading a higher capacity single compressor in conventional systems. Operating a larger compressor or a compressor with a wide range of capacity can include performance characteristics linked to reducing its capacity to more than half during unloading or spooling down. In some cases, the larger compressor may have to spool down below its recommended shaft minimum rotational speed in order to maintain proper balancing of the wheel itself and air bearing support (e.g. to prevent wobbling, or causing stall of the turbo machine itself). In other words, a larger compressor might be called to operate under less than optimal conditions in order to satisfy a bleed air demand that may entrain failure if below that recommended minimum speed. The advantage of running smaller compressors in parallel as described herein is the smaller compressors don't have to unload or spool down to the same low level minimum rotational speeds in order to reduce airflow capacity. Thus, aspects of the disclosure can include higher performance characteristics under a wider range of bleed air demands.

To the extent not already described, the different features and structures of the various embodiments can be used in combination with each other as desired. That one feature cannot be illustrated in all of the embodiments is not meant to be construed that it cannot be, but is done for brevity of description. Thus, the various features of the different embodiments can be mixed and matched as desired to form new embodiments, whether or not the new embodiments are expressly described. Moreover, while “a set of” various elements have been described, it will be understood that “a set” can include any number of the respective elements, including only one element. Combinations or permutations of features described herein are covered by this disclosure.

This written description uses examples to disclose embodiments of the invention, including the best mode, and also to enable any person skilled in the art to practice embodiments of the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and can include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. 

What is claimed is:
 1. An aircraft comprising: an environmental control system having a bleed air inlet; a gas turbine engine having at least one low pressure bleed air supply and at least one high pressure bleed air supply; a turbo air cycle machine having a rotationally coupled first turbine section, a second turbine section, and a first compressor section, and a selectively rotationally coupled second compressor section; an upstream turbo-ejector selectively fluidly coupling the low and high pressure bleed air supplies to the first turbine section and at least one of the first compressor section or the second compressor section; and a downstream turbo-ejector fluidly combining fluid outputs from at least one of the first turbine section or the second turbine section with fluid output from the at least one of the first compressor section or the second compressor section into a common flow that is supplied to the bleed air inlet of the environmental control systems.
 2. The aircraft of claim 1, wherein the first compressor section and the second compression section are in parallel.
 3. The aircraft of claim 2, wherein the first turbine section, the second turbine section, and the first compressor section are rotationally coupled to a common shaft.
 4. The aircraft of claim 3, further comprising at least one of a clutch assembly, a decoupling mechanism, or a mechanical fuse disconnect, configured to selectively couple the second compressor section to the common shaft.
 5. The aircraft of claim 1, further comprising a bypass conduit fluidly coupling the fluid output of the first turbine section to the downstream turbo-ejector.
 6. The aircraft of claim 5, further comprising a bypass valve configured to selectively control fluid flow through the bypass conduit.
 7. The aircraft of claim 1, further comprising a source valve fluidly coupling an ambient air supply to the low pressure bleed air supply in the upstream turbo-ejector.
 8. The aircraft of claim 7, wherein the source valve is configured to supply one of the ambient air supply or the low pressure bleed air supply to at least one of the first compressor section or the second compressor section.
 9. A method of providing air to the environmental control system of the aircraft of claim 1, the method comprising: selectively supplying at least some of ambient air, low pressure bleed air, or high pressure bleed air to the turbo air cycle machine to precondition the bleed air according to operational demands of the environmental control system; wherein the selectively supplying comprises selectively supplying to at least one of the first compressor section or the second compressor section based on desired flow capacity; and wherein the preconditioning comprises selectively providing a fluid output emitted from the first turbine section of the turbo air cycle machine to the second turbine section of the turbo air cycle machine for further cooling.
 10. The method of claim 9, further comprising selectively supplying a fluid output from the at least one of the first compressor section or the second compressor section of the turbo air cycle machine to a fluid output emitted from at least one of the first turbine section of the turbo air cycle machine or the second turbine section of the turbo air cycle machine.
 11. The method of claim 10, further comprising de-coupling the second compressor section.
 12. An aircraft comprising: an environmental control system having a bleed air inlet; a gas turbine engine having a low pressure (LP) bleed air supply and a high pressure (HP) bleed air supply; a turbo air cycle machine comprising a first turbine section, a second turbine section, a first compressor section, and a second compressor section; a controllable valve assembly located upstream of the turbo air cycle machine and comprising: a first fluid coupling between the LP bleed air supply and the first turbine section; a second fluid coupling between the HP bleed air supply and the first turbine section; and a third fluid coupling between the LP bleed air supply and at least one of the first compressor section or the second compressor section; and a turbo-ejector fluidly combining at least one turbine output flow from at least one of the first turbine section or the second turbine section with at least one compressor output flow from the at least one of the first compressor section or the second compressor section to form a common output flow that is supplied to the bleed air inlet.
 13. The aircraft of claim 12, further comprising a fourth fluid coupling from an outlet of the first turbine section to an inlet of the second turbine section, whereby a first turbine output flow is supplied to the second turbine section to form a second turbine output flow.
 14. The aircraft of claim 13, wherein the turbo-ejector fluidly combines the second turbine output flow from the second turbine section with the compressor output from the at least one of the first compressor section or the second compressor section to form the common output flow.
 15. The aircraft of claim 13, further comprising a bypass conduit fluidly coupling an outlet of the first turbine section to the turbo-ejector.
 16. The aircraft of claim 15, further comprising a bypass valve fluidly coupled to the outlet and configured to supply a first portion of the first turbine output flow to the second turbine section, and to supply a second portion of the first turbine output flow to the bypass conduit.
 17. The aircraft of claim 16, wherein the first portion is between 0-100% of the first turbine output flow.
 18. The aircraft of claim 13, wherein the turbo-ejector fluidly combines each of the first turbine output flow, the second turbine output flow, a first compressor output flow from the first compressor section, and a second compressor output flow from the second compressor section to form the common output flow.
 19. The aircraft of claim 13, further comprising an ambient air supply fluidly coupled to the controllable valve assembly.
 20. The aircraft of claim 19, wherein the controllable valve assembly is configured to supply one of the ambient air supply or the LP bleed air supply to at least one of the first compressor section or the second compressor section. 